Electromagnetic relay

ABSTRACT

An electromagnetic relay has a winding form, of plastic composition material, carrying the entire relay assembly, has an armature movably supported in the winding form, and has at least one set of contact springs supported on the winding form and including plural contact springs and resilient cooperating contacts electrically isolated from each other by dielectric material. The contact springs and the cooperating contacts are formed with cutouts in the area of the dielectric material, and the relay further includes a magnet yoke. The coil form has flanges at both ends, and the flanges are formed with slots which are symmetrical and parallel to the longitudinal center line of the armature and perpendicular to the length of the winding form, these slots being defined, in part, by lamellae of plastic composition material. The contact springs, resilient contacts, relay winding terminals and legs of the magnet yoke are mounted in the slots and locked in position by deformation of the plastic composition material into the cutouts, such deformation being effected by melting and flowing of the plastic composition material. The melting and flowing of the plastic composition material may be effected ultrasonically.

United States Patent Wahnschaffe ELECTROMAGNETIC RELAY 72 Inventor: Klaus-Dieter Wahnschafie, 3150 Peine/Hann., Saarlandring 19 D, Germany [22] Filed: July 27, 1971 [21] Appl. No.: 166,518

[30] Foreign Application Priority Data July 31, 1970 Germany .P 20 38 236.9

[52] US. Cl. ..335/133, 200/166 J [51] Int. Cl. ..H01h [58] Field of Search ..335/133, 250,126,131,196, 335/202, 135; 200/166 J, 166 BH [56] References Cited UNITED STATES PATENTS 3,377,450 4/1968 Grady et al. ..200/166 J 3,242,285 3/1966 Obszarnys et al ..335/202 2,831,939 4/1958 Alizon et al. ..335/135 3,172,272 3/1965 Schleicher ..335/202 [57] ABSTRACT An electromagnetic relay has a winding form, of plastic composition material, carrying the entire relay assembly, has an armature movably supported in the winding form, and has at least one set of contact springs supported on the winding form and including plural contact springs and resilient cooperating contacts electrically isolated from each other by dielectric material. The contact springs and the cooperating contacts are formed with cutouts in the area of the dielectric material, and the relay further includes a magnet yoke. The coil form has flanges at both ends, and the flanges are formed with slots which are symmetrical and parallel to the longitudinal center line of the armature and perpendicular to the length of the winding form, these slots being defined, in part, by lamellae of plastic composition material. The contact springs, resilient contacts, relay winding terminals and legs of the magnet yoke are mounted in the slots and locked in position by deformation of the plastic composition material into the cutouts, such deformation being effected by melting and flowing of the plastic composition material. The melting and flowing of the plastic composition material may be effected ultrasonically.

8 Claims, 4 Drawing Figures PATENTED 3.702.981

sum 2 or 2 INVENTOR KLhus-mETER umuuscunm' I BY 7 r g HT OKN ELECTROMAGNETIC RELAY FIELD OF THE INVENTION This invention relates to' electromagnetic relays and,

more particularly, to a novel and improved electromagnetic relay in which the contacts of the relay are precisely mounted in a plastic winding form in a simple and inexpensive manner.

BACKGROUND THE INVENTION flange, recessed chambers for the lateral guidance of the contact springs. Furthermore, soldering lugs, designed as the fixed contacts, are inserted into these chambers and are press-fitted into grooves cut into the winding form. The contact springs are secured, at their other ends, in the second winding form flange by means of a base plate pressed against the ends of the contact springs by cup springs, with the cup springs being designed as resilient retaining ringswhich surround a pin attached to the winding form and engage with grooves in this pin. The contact springs are actuated by an actuator cam which is operatively connected with the resilient magnetic armature of the relay, and are movably supported in grooves formed in the first flange of the winding form. The pins serve, at the same time, as fastening means for themagnet yoke and the magnet armature.

An important shortcoming of this relay is found to be the attachment of the contact springs at the flange of the winding form. In order to fix the contact springs absolutely, the base plate of the relay must exert a high pressure on the contact springs. To this end, the retaining springs, arranged in the center part of the base plate, are pretensioned and placed'around the mounting pins in such a manner that bending of the base plate is unavoidable. By deformation of the base plate, the soldering lugs, which are arranged at right angles to the contact springs, are at the same time skewed with respect to the flange of the winding form. If the relay is plugged into a relay socket, proper contact consequently is not always assured.

Although the soldering lugs, designed as the fixed contacts, are press-fitted into the grooves of the winding form, and are secured against extraction by virtue of their angular design and by projections of the winding form made by heat, the lugs can move in their grooves. Thereby, tilting of the soldering lugs and oblique positioning of the fixed contact surfaces caused thereby is not impossible, so that constant contact pressure of the contact springs cannot be maintained.

In another known electromagnetic relay shown in Swiss Pat. No. 452,704, the winding form also is designed so that it carries the entire relay assembly, serving at the same time as support for several sets of springs arranged side-by-side on the terminal side as well as on the contact side. On the contact side, the winding form or coil form is provided with step-like rest, which fixes the mutual position of the contact springs of each individual contact. Into the central hole of the winding form there is inserted the center leg of a magnet yoke designed in E-shape. The magnet yoke is fastened by the magnet armature, which is designed asv a flat, U-shaped part, resiliently supported on the magnet yoke. The armature, with its inside, makes contact with one surface of the winding form and closes the magnetic circuit, in the energized condition, through the individual, free-standing legs of the magnet yoke.

At the rear flange of the winding form there is attached a set of contact springs which consists of several contact springs arranged on top of each other, and which are electrically isolated from each other by insulating or dielectric spacers. Such series of contacts can be arranged in multiples over the width of the relay, in which case the insulating or dielectric spacers must be correspondingly enlarged.

In order to secure the individual contact springs in the set of contact springs, the spacers are pressed together by a screw.' The contact spring pressure exerted thereby on the ends of the contact assures that they cannot be moved laterally. The free ends of the contact springs engage with rests which are arranged at the second flange of the winding form and are recessed in step fashion. Although the spacing between the individual contact springs is defined thereby, equal tension of all the contact springs of a set, arranged side-byside, is not attained. The pretension depends individually on the spring constants and the deformations that might occur in blanking. The magnet coil terminals are secured in the winding form by casting. In the manufacture of such a relay, care must be taken, during assembly, that the contact springs are aligned in a row, so that the contact rivets make contact when the contact springs are actuated. Furthermore, the fastening screws must be tightened in such a manner that lateral shifting of the contact springs is no longer possible. To receive the screws, recesses are made inthe spacers and the contact springs, and the size of these recesses is so chosen that the electrically conductive screws do not come in contact with individual contact springs. One solution, in accordance with this Swiss patent, provides furthermore that an insulating sleeve is initially inserted into the common hole, and has the fastening screw inserted thereinto. Thereby, any possibility of an undesired contact is excluded.

It will be seen that, for the manufacture of a relay of this kind, a multiplicity of different parts is required. There is a further drawback in the adjustment of the contact springs as, due to the spacings between the individual rows of contact springs, bending of the individual contact springs is possible only with special tools.

In an electromagnetic relay, with wire contact conductors, disclosed in German Pat. No. 445,268, the terminal ends, protruding through a support plate, are bent and supported in corresponding holes of the support plate in such a manner that they constitute a resilient mounting of the conductors. Due to this resiliency, these terminal ends are held in the holes in the support plate without special means of attachment. However, the assembly of the contact springs, in this relay, is difficult and time-consuming.

As disclosed in German Pat. No. 972,767, individual contact elements of sets of contact springs are placed in slots cut in a plastic base and secured therein by means of a thermoplastic resin. This method, also, is time-consuming, inasmuch as the contact elements must be inserted into the slots and kept in their position until the thermoplastic resin, for closing the slots, is applied to the base which has been made plastic by heating, pushed into the slots, and let set after cooling. Finally, there is known, through German Utility Pat. No. 6,660,429, an electromagnetic relay for signaling apparatus in motor vehicles, and which has a magnetic core with is surrounded by a winding form consisting of insulating or dielectric material. The relay further has an armature supported by a resilient metal sheet, and a contact part forming the contact opposite to the contact moved by the armature, or carrying this opposite contact. In this relay, the winding form has two extensions each of which is formed with one through-hole, into which is inserted, in a selflocking manner or riveted, the contact part forming or supporting the opposite contact as well as a further contact part holding the spring metal sheet. If this relay is to be used to accommodate several contact springs, the individual springs must be tensioned in their receptacles, but a desired securing of the contact springs, as to their mutual position, is not assured, so that constant contact pressure can be obtained in this type of relay only by subsequent adjustment of the contact springs.

SUMMARY OF THE INVENTION The objective of the present invention is to provide an electromagnetic relay which can be manufactured by simple production processes and economically without any time-consuming assembly due to special alignment, fastening and subsequent adjustment of the individual contact elements, and which has a readily visible contact arrangement.

In accordance with the invention, the winding form has, in a manner known per se, flanges on both sides, and there are provided in the flanges, symmetrically and parallel to the longitudinal center line of the magnetic armature, and perpendicular to the longitudinal axis of the winding form, slots or recesses in which the contact springs and their resilient opposite contacts or counter springs, or the soldering lugs designed as the opposite contacts, as well as the legs of the magnet yoke, are secured and fastened by melting the plastic material of the laminations forming the slots into the recesses or cutouts of the contact elements and of the legs of the magnet yoke, as well as by fusing together the plastic material of the protruding laminations in a form-locking manner.

The invention attains the technical advance that, due to the symmetrical, mirror-like design, a set of contact springs can be closed and another set of contact springs opened simultaneously with only one movement of the armature. Moreover, it is no longer necessary that the contacts are inserted by hand, as has been up to now, and secured by several operations, as the insertion and securing of the contact springs is effected mechanically by only two successive operations, the contact springs being introduced mechanically into the slots and being kept in this position until the contact springs and their opposite springs are secured in a form-locking manner by melting the protruding plastic. The contact springs are seated firmly in the slots without any tensioning, and need not be adjusted subsequently to compensate for stresses in the spring material.

Relays, whose magnetic yokes consist of U-shaped blanked laminations and whose magnet yoke legs are arranged perpendicularly to the longitudinal axis of the winding form and perpendicularly to the flange sur' faces, have, in a further embodiment of the invention, slots worked into the flanges into which the contact elements and the legs of the magnet yoke are inserted and fastened by melting the plastic material of the laminations forming the spots into the recesses or cutouts of the contact elements and of the magnet yoke legs, in a formlocking manner. In order to save material at the winding form flanges, these flanges are made with thin walls and the slots are worked into extensions-attached to the flanges. The contact elements and the legs of the magnet yoke are fastened in the slots of the extensions in the manner described.

If the tip of the slots is chosen, in a manner known per se, to be larger than the width of the'contact element or of the magnetic yoke leg to be inserted, a further advantage can be realized by melting the plastic material to flow together outwardly of the contact elements or the magnet yoke legs. With the internal heating of the plastic material of the laminations, the material not only flows into the recesses or cutouts of contact elements of magnet yoke legs, but also fuses together the remainder of the slot. This results in an additional solidification of the coil form in the manner of a solid block.

To actuate the contact springs, protruding laterally with respect to the armature extending from the winding form, there is attached to the magnet armature, in accordance with the invention, a contact slider which is operatively connected with the hinged or resilient contact springs. In order to increase the number of contacts, there are arranged at both ends of the movable armature, and parallel to the latters longitudinal center line at one or both flanges, contact springs and counter springs, or resilient opposing contacts, or soldering lugs designed as fixed contact. These are inserted into slots formed in the extensions attached to the flanges, and are secured by welding or fusing the plastic material into recesses or cutouts of the contact elements. Through this unconventional relay design, the number of contact elements on opposite sides of the moving armature, at each flange of the winding form, can be expanded at will.

With the one-piece construction of the winding forms, it is assured that the dimensions always have the same tolerances. This applies to the exterior dimensions as well as to the interior dimensions of the recesses and slots. In assembly, the already bent contact springs on the other contact elements are pushed edgewise into the slots. The accuracy, as to the magnitude of the slot width, assures that, with proper choice of tolerances, the contact elements are firmly seatedafter insertion.

As the contact elements are inserted into the slots, they are pushed inwardly until their narrow edges abut the rear walls of the slots. Thereby, the contact elements align themselves so that the contact rivets are in alignment on top of each other or laterally, respectively, provided the lengths protruding from the slots are maintained. As the prefabricated or pre-bent springs are not subject to any deformation during insertion, no

subsequent adjustment is necessary in the course of the further manufacturing operations. In a manner similar to the contact elements, the legs of the magnet yoke also are inserted into theslots. Tolerances of the slot widths and magnet yoke legs facings on thicknesses, suitably selected, likewise assure that a firm seating in the slot exists immediately upon insertion. After inserting, ultrasonic tools, by .means of which the plastic material is made to flow, are pressed against the laminations or the lateral surfaces of the recesses. The flowing plastic penetrates into the recesses or cutouts of the contact elements and the magnetic yoke legs. If, in this procedure, the ultrasonic tool is placed across two laminations, the plastic material of both laminations, which penetrates into the recesses or cutouts of the contact elements and the magnet yokes, is fused together, so that the entire winding form, with the inserted contact elements and the magnet yokes, forms a solid block unit.

Such relays are extremely shock-resistant. No screws are used for securing the contact elements and the magnet yokes, and time-consuming assembly work thereby is eliminated. In the event of a change in contact pressure, through readjustment of the contact springs, the arrangement of the relay assures that all contacts are readily accessible. Contact bum-off at the contact rivets can be ascertained quickly and without effort, because the contact arrangement is clearly visible. By this method of manufacturing electromagnetic relays, manufacturing costs are substantially reduced and it is thereby made possible to produce a very attractively priced relay. Individual operations, such as were necessary in the manufacture of conventional relays to make the individual different contact springs, spacers, relay base plates, fastening pins for the magnet yokes, and the like are no longer required and can be dispensed with if the principles of the invention are applied.

An object of the invention is to provide an improved electromagnetic relay.

Another object of the invention is to provide such a relay which is simple and inexpensive to manufacture and assemble.

A further object of the invention is to provide such a relay which is extremely shock-resistant;

Another object of the invention is to provide such a relay in which all the relay contacts are readily assessible.

For an understanding of the principles of the invention, reference is made to the following description of typical embodiments thereof as illustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a side elevation view of an electromagnetic relay in accordance with the invention including two U- shaped magnet yokes blanked out of sheet metal and having contact springs and their counter springs arranged at both sides of the movable armature at each flange of the winding form;

FIG. 2 is an end elevation view of the electromagnetic relay shown in FIG. 1;

FIG. 3 is a perspective view of a winding form, embodying the invention, without receptacles for the legs of the magnet yokes; and

( Thereby the plastic material penetrates into recesses or FIG. 4 is a partial perspective view of the contact elements or magnet yoke legs in the area of the cutouts provided for incorporation into the winding form, and

illustrating two different forms of cutouts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, the electromagnetic relay shown therein comprises a winding form 1 having a magnetizing winding 2 wound on it, winding form 1 having two flanges 3, one on each side, and each having an extension 4. Winding form 1 has a central aperture 5 therethrough containing a pair of bearing plates 6 which bearing plates support a movable armature 7 which extends perpendicularly through winding form 1 at the center of the latter. Each opposite end of armature 7 has secured thereto a respective actuator slider 8 which is operatively connected with contact springs 10 through driving pins 9. Each contact spring 10 has a pair of counter springs 11, one arranged on each side. Two soldering lugs.12 serve as terminals for applying a potential to winding 2. When winding 2 is energized, the magnetic circuit is closed through the magnet yokes 13a and 13b, which are U-shaped. The bases 15 of the magnet yokes 13a and 13b are spaced apart by a permanent magnet 14.

Flanges 3 of winding form 1 are formed with slots 17 toreceive the legs 16 of the magnetic yokes, and the width ofthese slots is chosen according to the thickness of the legs 16. In the area of central aperture 5, laminations 20, facing this central aperture, are removed, so that the inner surfaces of legs 16, with proper correlation, can line up with the edges of aperture 5. With magnet yokes 13a and 13b inserted, a minimum air gap is obtained between the inner surfaces of the magnet yoke and the outer surfaces of armature 7 facing these inner surfaces. After insertion of leg 16 into the respective slots 17 of flanges 3, ultrasonic tools are pressed against the surfaces of the material which form the slots, and cause the plastic material to flow, after the energy source is connected, in the area of the slots.

cutouts 18 in magnet yoke legs 16 in this area, so that an absolutely firm seating of magnet yokes 13a and 13b in flanges 3 is assured.

Extensions 4 of the flanges 3 of winding form 1 are also formed with slots 19 for receiving contact springs 10 and counter springs 11, the depth of these slots, relative to the depth of slots 17, being so chosen that, after insertion of contact springs 10 and counter springs 11, there remains a residual portion of each slot. When the contact springs 10 and counter springs 11 are inserted, they are pushed in until their edges abut against the rear walls of the slots 19, so that any aligning of the individual contact springs 10 and counter springs 11 becomes unnecessary. Contact springs 10 and counter springs 11 also have recesses or cutouts 18 in the area of the slots 19 so that, upon heating of the plastic material of the laminations 20, forming the slots 19, the plastic material can flow into the recesses or cutouts 18. At the same time, the plastic material of laminations 20 is fused together in the remainder of the slots, so that a compact solid unit of the winding form with the individual parts is created. In the same manner as contact springs 10 and counter springs l 1 are secured in a form-locking manner in extensions 4 of the flanges of winding form 1, so also are soldering lugs 12, for supplying current to winding 2, inserted into slots 19 in extensions 4. The melting of the plastic material of the larnellae or laminations 20, forming the slots, is accomplished in the same manner, by means of ultrasonic tools, with the plastic penetrating into the recesses or cutouts 18 of the soldering lugs so that the latter are firmly fixed against any movement.

As winding form 1, consisting of plastic composition material, is made by injection molding or by a pressure casting processes, it is assured that the dimensions of the slots, and those of the other details of winding form 1, are constant so that subsequent adjusting operations are made unnecessary to the greatest possible extent.

In a simplified representation, a winding form 1, designed in accordance with the invention, for a relay with a movable armature 7 supported in a central aperture 5 of the winding form is shown in FIG. 3. The securing means for the magnet yokes 13a and 13b are not shown. As can be clearly seen from this perspective view, on both sides of the movable armature 7 and extending parallel to its longitudinal center line, which is located in the center of winding form 1, there are fixed, at the flanges 3 of winding form 1, contact springs 10 and counter springs 11 which are secured in slots 19 formed in extensions 4 of flanges 3 in a form-locking manner. The depth of the slots here is chosen to be greater than the width of the contact elements. Upon heating the plastic material of laminations 20 forming slots 19, the plastic material of each of two adjacent slot forming laminations and those portions of the slots outwardly of the contact springs 10 and counter springs 11 fuse with each other and, at the same time, the plastic material of laminations 20 penetrates into the recesses or cutouts 18 of springs 10 and 11. An absolutely firm seating of contact springs 10 and counter springs. 11 is thereby assured. Furthermore, the unstable, comb-like structure of smaller extensions 4 is eliminated by the fusing, and the extensions 4 form a compact stable unit with flanges 3. Contact springs 10 are actuated by sliders 8 which has fork-shaped cutouts at its opposite ends engaging contact springs 10. Sliders 8 are rigidly connected with armatures 7. On winding form 1, winding 2 is wound between flanges 3, and the sleeves are not shown in FIG. 3.

When welding in the contact elements, winding form 1 with the inserted contact elements is placed in a fixture. The pressing on of the ultrasonic tool takes place mechanically and fully automatically, and can be programmed controlled so that heating of the plastic surface is avoided.

FIG. 4 illustrates a section of the contact elements or of the magnetic yokes in the area of the slots 17 and 19, and form with recesses or cutouts. At the center of the section shown in FIG. 4, there are illustrated recesses or cutouts 37 in both edges of the contact element. Above these cutouts or recesses, there is illustrated an elongated cutout or opening 38 while, below cutouts 37, there is illustrated a generally circular hole 39. After the plastic material has penetrated into such recesses or cutouts, such as the recesses or cutouts 37, 38 and 39, the individual form-like parts are absolutely fixed and cannot be pulled out of the slots even though the use of considerable force.

It should be understood that the invention is not limited to the particular embodiments illustrated, as the application of the principles of the invention permits designing a relay with a particularly attractive price and which is simple from a manufacturing point of view. For this reason, the invention can be applied also to other types of relays which are not shown in the drawings, as well as to relays'which have more than one coil or winding system.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be'embodied otherwise without departing from such principles.

What is claimed is:

1. In an electromagnetic relay of the type having a winding form, of plastic composition material, carrying the entire relay assembly, an armature movably supported in the winding form, at least one set of contact springs supported on the winding form and including plural contact springs, movable by the armature, and resilient cooperating contacts electrically isolated from each other by dielectric material, the contact springs and cooperating contacts being formed with cutouts in the area of the dielectric material, and a magnet yoke, the improvement comprising, in combination, said coil form having flanges at both ends; said flanges being formed with slots which are symmetrical and parallel to the longitudinal center line of said armature and perpendicular to the left of said winding form, and which are defined, in part, by lamellae of plastic composition material; at least said contact springs and said resilient contacts being mounted in said slots and locked in posi tion by deformation of the plastic composition material into cutouts therein.

2. In an electromagnetic relay, the improvement claimed in claim 1, including soldering lugs, designed as fixed contacts, and magnet yoke legs mounted in said slots and locked in position by deformation of the plastic composition material into cutouts therein.

3. In an electromagnetic relay, the improvement claimed in claim 2, in which said slots are formed in extensions of said flanges extending laterally from said flanges.

4. In an electromagnetic relay, the improvement claimed in claim 2, in which the depth of said slots are greater than the widths of the components inserted and seated against the bottoms of said slots; the components inserted in said slots being further locked against extraction from the associated slots by deformation of the plastic material forming those portions of the slots outwardly of the inserted components into locking engagement with the inserted components.

5. In an electromagnetic relay, the improvement claimed in claim 2, in which said winding form is a onepiece body of plastic composition material.

6. In an electromagnetic relay, the improvement claimed in claim 5, in which said winding form is a casting.

7. In an electromagnetic relay, the improvement claimed in claim 5, in which said winding form is an injection molded body.

8. In an electromagnetic relay, the improvement claimed in claim 2, in which said armature is an elongated armature extending through a central aperture in said winding form and projecting from said winding form at each end; and respective contact sliders secured to the opposite ends of said armature and engaged with said contact springs. 

1. In an electromagnetic relay of the type having a winding form, of plastic composition material, carrying the entire relay assembly, an armature movably supported in the winding form, at least one set of contact springs supported on the winding form and including plural contact springs, movable by the armature, and resilient cooperating contacts electrically isolated from each other by dielectric material, the contact springs and cooperating contacts being formed with cutouts in the area of the dielectric material, and a magnet yoke, the improvement comprising, in combination, said coil form having flanges at both ends; said flanges being formed with slots which are symmetrical and parallel to the longitudinal center line of said armature and perpendicular to the left of said winding form, and which are defined, in part, by lamellae of plastic composition material; at least said contact springs and said resilient contacts being mounted in said slots and locked in position by deformation of the plastic composition material into cutouts therein.
 2. In an electromagnetic relay, the improvement claimed in claim 1, including soldering lugs, designed as fixed contacts, and magnet yoke legs mounted in said slots and locked in position by deformation of the plastic composition material into cutouts therein.
 3. In an electromagnetic relay, the improvement claimed in claim 2, in which said slots are formed in extensions of said flanges extending laterally from said flanges.
 4. In an electromagnetic relay, the improvement claimed in claim 2, in which the depth of said slots are greater than the widths of the components inserted and seated against the bottoms of said slots; the components inserted in said slots being further locked against extraction from the associated slots by deformation of the plastic material forming those portions of the slots outwardly of the inserted compoNents into locking engagement with the inserted components.
 5. In an electromagnetic relay, the improvement claimed in claim 2, in which said winding form is a one-piece body of plastic composition material.
 6. In an electromagnetic relay, the improvement claimed in claim 5, in which said winding form is a casting.
 7. In an electromagnetic relay, the improvement claimed in claim 5, in which said winding form is an injection molded body.
 8. In an electromagnetic relay, the improvement claimed in claim 2, in which said armature is an elongated armature extending through a central aperture in said winding form and projecting from said winding form at each end; and respective contact sliders secured to the opposite ends of said armature and engaged with said contact springs. 